I searched about this but couldn't find anything. I'm in Australia so set the Time Offset to 16. It works fine at first. But after coming back to the site later on the offset is put back to 5. This happens on both my laptop and desktop. I'm using Firefox on both. Is this a known problem?

I just tried it on the laptop, telling the site to remember me, closed firefox then opened it again and the timezone was correct. But after logging out and back in it reset back to offset 5 instead of 16. I've cleared cookies etc several times but it keeps happening.